An often-fatal brain disease—progressive multifocal leukoencephalopathy (or PML)—has been known to be associated with people who take Tysabri for treatment of Multiple Sclerosis.
But, a recent report shows that PML may be associated with a person with MS who contracted PML while on the more recent new drug, Gilenya, made by Novartis.
The United States government is investigating the connection through the Food and Drug Administration to see what connection there may be if any between the case in Europe of the person getting the rare brain infection and taking Gilenya.
Doctors and officials are saying it is too early for people taking Gilenya to be concerned about getting off the medication at this point.
PML was previously associated with Tysabri, made by Biogen Idec, and the patient in Europe was never on that medication.
Representatives for Novartis wrote to Reuters (the news agency that broke the story) and said that they doubted that the brain infection could be attributed to Gilenya because the patient had been only on the medication for little more than half a year.
"With over 71,000 patients having been treated with Gilenya, there has been no previous case of PML attributable to Gilenya," Novartis said.
Gilenya was approved in the United States in September 2010 and Tysabri was approved by the FDA in 2004, but was taken off the market due to concerns over PML.